Elution of normal granulocytes from nylon fibers, using cationic anesthetics, indicate that tetracaine-eluted cells were comparable to non-filtered controls in viability, micromorphology, and phagocytic competence. Detachment from the fibers by these agents appears to occur by a mechanism not damaging to plasma membranes and cell constituents. BIBLIOGRAPHIC REFERENCE: Sanel, F.T., Aisner, J., Schiffer, C.A.: Filtration leukopheresis. Blood 47:877-878, 1976.